By adding 0.0005% ~ 0.0030% of boron, Boron steel series refine grain size organization to improve the hardenability .The bolt produced with boron steel equivalent 35K can reduce the carbon content and alloy content, and improve the cold working properties. This is omitted the spheroidizing annealing of medium carbon steel bolt. Boron steel can process bolts of grade 8.8 ~ 10.9, the bolt of 10.9 is the upper limit of application of boron steel. In theory, in accordance with the processing technic ,the final products of boron steel can be divided into hardened and tempered steel and non-quenched and Tempered Steel.

　　According to different specifications, the 10B21 steel wire rod of Xingtai Steel can be divided into three categories due to their end use: carburizing screws, Fastener of grade8.8~10.9 and bicycle parts, the table as below.

　　With good ductility and cold heading properties and good hardenability, the 10B21 of Xingtai steel can omit the spheroidizing annealing of medium carbon steel bolt.

　　The products of our company are sold to many well-known standard parts enterprises of foreign and domestic funds in eastern and southern China. Some bicycle parts manufacturing plant use our products to produce bicycle axis and then export to Europe and America, and the users reflect well.